Bitter taste phenotype as a risk factor of oral nicotine replacement nonadherence The broad objective of this exploratory experiment is to generate data on the interaction of bitter taste phenotype and use of oral nicotine replacement therapy (NRT) during smoking abstinence. Approximately 70% of the population taste bitter, while 30% do not taste bitter. Nicotine is a bitter compound. Specific aims are: 1) To examine the effect of bitter taste phenotype (BTP), as determined by 6-n-propylthiouracil (PROP) taste methodology, on participants use of two oral NRT products (nicotine inhaler and lozenge for 1 week each) in cigarette smokers during smoking abstinence. 2) To characterize the effect of BTP on sensory experiences of two oral NRT products (nicotine inhaler and lozenge for 1 week each). 3) To investigate differences in use of the two oral NRT products comparing continuous (lozenge) versus intermittent (inhaler) exposure by BTP. There has been limited research to differentiate the various forms of NRT from each other in clinical effectiveness. Individualizing NRT product type based on the smoker s unique characteristics, such as bitter taster or nontaster of bitter, may improve treatment adherence and ultimately increased smoking cessation. The recently released Institute of Medicine report entitled Ending the Tobacco Problem: A Blueprint for the Nation stresses the social benefits to the country of reduced smoking prevalence. The mission of the National Institute on Drug Abuse is research that leads to improved prevention, treatment and policy related to drug addiction, including nicotine. In relation to the area of improved treatment, a repeated measures crossover experimental design will be implemented to address the specific aims above. Potential participants will be tested for bitter taste phenotype, a noninvasive clinically applicable procedure. Half of the sample of 124 will be bitter tasters and half will not taste bitter. Participants will be randomly assigned to order of oral NRT product with half of participants experiencing 1 week of nicotine lozenge followed by 1 week of nicotine inhaler and the other half experiencing the reverse. Data will be collected at baseline and the end of weeks 1 and 2. Outcome variables include NRT adherence (the number of oral NRT products used each week), participants sensory experience of each product (logs), cotinine concentrations at the end of each week in comparison to baseline as a monitor of adherence to nicotine replacement, and carbon monoxide measurement to determine smoking status. Determining whether bitter taste phenotype operates as an NRT adherence risk factor will inform the search for individually optimized use of oral NRT product during the smoking cessation process. PUBLIC HEALTH RELEVANCE: It is critical to reduce the 45 million cigarette smokers in the United States and smoking cessation pharmacotherapy doubles or triples one s chances of successful quitting. However, these products such as oral nicotine replacement therapies are not fully utilized with one potential factor being whether the smoker is a bitter taster or non-taster of bitter. Since nicotine contained in oral nicotine replacement medication has a bitter taste and 70% of the population taste bitter, using a simple technique in the clinical setting to match an individual s bitter taste type to appropriate nicotine or non-nicotine smoking cessation medications may be relevant to increase smoking cessation success.